CN217472733U - Trioxymethylene's response device and production system thereof - Google Patents
Trioxymethylene's response device and production system thereof Download PDFInfo
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- CN217472733U CN217472733U CN202220245910.6U CN202220245910U CN217472733U CN 217472733 U CN217472733 U CN 217472733U CN 202220245910 U CN202220245910 U CN 202220245910U CN 217472733 U CN217472733 U CN 217472733U
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Abstract
The utility model discloses a trioxymethylene's response device and production system relates to chemical production equipment technical field to solve the purity of the trioxymethylene that the reaction made low, problem with high costs. The trioxymethylene reaction equipment comprises: the catalytic rectifying tower comprises a plurality of reaction units distributed along the height direction of the catalytic rectifying tower, and each reaction unit comprises a solid acid catalyst bed layer and a gas-liquid phase mass transfer structure distributed along the height direction of the catalytic rectifying tower. The trioxymethylene production system comprises the trioxymethylene reaction equipment provided by the technical scheme. The utility model provides a trioxymethylene's response device and production system are used for preparing trioxymethylene.
Description
Technical Field
The utility model relates to a chemical production equipment technical field especially relates to a trioxymethylene's response device and production system thereof.
Background
At present, a kettle reactor can be used to generate a trioxymethylene-containing reaction product by using 65% -75% formaldehyde solution as a raw material and performing a trimerization cyclization reaction on the formaldehyde solution under the catalytic action of concentrated sulfuric acid. The concentration of trioxymethylene in the reaction product is 15-20%. When the trioxymethylene is purified from the reaction product, the reaction product can be firstly fed into a concentration tower, the concentration of the trioxymethylene is increased to more than 50%, so as to obtain a ternary azeotrope of formaldehyde, water and trioxymethylene, then the ternary azeotrope is fed into an extraction tower, benzene is used as an extracting agent, the trioxymethylene is extracted from a water phase to an oil phase to form a mixture of the trioxymethylene and the benzene, then the mixture of the trioxymethylene and the benzene is fed into a product tower, the benzene is obtained at the tower top of the product tower and is recycled as the extracting agent, and the trioxymethylene is obtained at the tower bottom of the product tower.
However, the reaction for polymerizing formaldehyde to generate trioxymethylene is a reversible reaction, and the equilibrium conversion rate and the single-pass conversion rate of the reaction are low, so that the energy consumption for preparing trioxymethylene is high. And because the catalyst used in the reaction is concentrated sulfuric acid, the liquid homogeneous reaction is carried out in the kettle-type reactor, so that the catalyst and reaction materials are difficult to separate, the product purity is reduced, meanwhile, the kettle-type reactor is corroded, and the reaction time and the reaction cost are improved.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a trioxymethylene's response device and production system for improve the purity of the trioxymethylene that the reaction made, reduce energy consumption and reaction cost.
In order to achieve the above object, the present invention provides the following technical solutions:
a trioxymethylene reaction device comprises a catalytic rectification tower, wherein the catalytic rectification tower comprises a plurality of reaction units distributed along the height direction of the catalytic rectification tower, and each reaction unit comprises a solid acid catalyst bed layer and a gas-liquid phase mass transfer structure distributed along the height direction of the catalytic rectification tower.
In the same reaction unit, the solid acid catalyst bed layer and the gas-liquid phase mass transfer structure are distributed along the height increasing direction of the catalytic rectification tower. Or in the same reaction unit, the solid acid catalyst bed layer and the gas-liquid phase mass transfer structure are distributed along the height reduction direction of the catalytic rectification tower.
Compared with the prior art, the utility model provides an among trioxymethylene's the response device, catalytic distillation column includes a plurality of reaction units along the direction of height distribution of catalytic distillation column, and every reaction unit includes solid acid catalyst bed and the gas-liquid phase mass transfer structure along the direction of height distribution of catalytic distillation column. Based on the above, when the formaldehyde solution is fed into the catalytic rectification tower, the solid acid catalyst bed layer is used for catalyzing the formaldehyde solution to perform trimerization cyclization reaction to obtain a liquid-phase reaction product containing trioxymethylene, at the moment, the liquid-phase reaction product containing trioxymethylene is separated in the gas-liquid phase mass transfer structure to separate part of trioxymethylene in the liquid-phase reaction product containing trioxymethylene, then the liquid-phase reaction product containing trioxymethylene flows into the next reaction unit, and so on, the equilibrium limitation of the reversible reaction is broken through continuously reducing the concentration of the reaction product, the one-way conversion rate of formaldehyde is improved, and thus the concentration of trioxymethylene prepared by the reaction is improved.
And simultaneously, the utility model provides an among the trioxymethylene's the reaction unit, choose for use solid acid catalyst to replace traditional concentrated sulfuric acid catalyst, solid acid catalyst is solid-state, and separates easily between the liquid reaction mass, has saved reaction time. And the corrosion degree of the solid acid catalyst to the catalytic rectifying tower is lower than that of concentrated sulfuric acid, so that in practical application, the catalytic rectifying tower made of 316L stainless steel can be selected, and the manufacturing cost of reaction equipment is reduced.
The utility model also provides a trioxymethylene's production system. The trioxymethylene production system comprises trioxymethylene reaction equipment and separation and purification equipment, wherein the trioxymethylene reaction equipment is communicated with an outlet of a catalytic rectification tower contained in the trioxymethylene reaction equipment.
Compared with the prior art, the utility model provides a trioxymethylene's production system's beneficial effect and above-mentioned technical scheme trioxymethylene's reaction equipment's beneficial effect is the same, and the here is not repeated.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and do not constitute a limitation on the invention. In the drawings:
fig. 1 is a schematic structural diagram of a trioxymethylene production system provided by the embodiment of the present invention;
fig. 2 is a schematic structural diagram of a part of a catalytic reaction section of a catalytic distillation tower provided by an embodiment of the present invention.
Reference numerals:
1-catalytic rectification tower, 11-rectification section;
12-catalytic reaction section, 13-stripping section;
2-extraction tower, 3-product tower;
4-phase separation device, 5-recovery tower;
6-reaction unit, 61-solid acid catalyst bed;
62-gas-liquid phase mass transfer structure, 7-preheater;
8-physical filter, 9-ion exchange filter.
Detailed Description
In order to make the technical problem, technical solution and beneficial effects to be solved by the present invention more clearly understood, the following description is made in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise. The meaning of "a number" is one or more unless specifically limited otherwise.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
Trioxymethylene is colorless needle crystal at normal temperature, has a melting point of 64 ℃ and a boiling point of 114.5 ℃, can be dissolved in water and various organic solvents, is an important intermediate for synthesizing Polyformaldehyde (POM) from formaldehyde, and is mainly used in the synthesis process of anhydrous formaldehyde.
The existing production process of trioxymethylene uses a kettle type reactor and takes 65% -75% concentration formaldehyde solution as raw material, under the catalysis of concentrated sulfuric acid, the formaldehyde solution is subjected to trimerization cyclization reaction, and a reaction product containing trioxymethylene is generated. The concentration of trioxymethylene in the reaction product is 15% -20%. When the trioxymethylene is purified from the reaction product, the reaction product can be firstly fed into a concentration tower, the concentration of the trioxymethylene is increased to more than 50%, so as to obtain a ternary azeotrope of formaldehyde, water and trioxymethylene, then the ternary azeotrope is fed into an extraction tower, benzene is used as an extracting agent, the trioxymethylene is extracted from a water phase to an oil phase to form a mixture of the trioxymethylene and the benzene, then the mixture of the trioxymethylene and the benzene is fed into a product tower, the benzene is obtained at the tower top of the product tower and is recycled as the extracting agent, and the trioxymethylene is obtained at the tower bottom of the product tower. Meanwhile, some low-concentration formaldehyde solution generated in the purification process of the trioxymethylene is sent to a recovery tower, a certain amount of wastewater is separated from the bottom of the recovery tower, and the formaldehyde solution obtained from the top of the recovery tower is further concentrated and then returns to the kettle-type reactor.
However, the reaction for polymerizing formaldehyde to generate trioxymethylene is a reversible reaction, and the equilibrium conversion rate and the single-pass conversion rate of the reaction are low, so that the energy consumption for preparing trioxymethylene is high. And because the catalyst used in the reaction is concentrated sulfuric acid, the liquid homogeneous reaction is carried out in the kettle-type reactor, so that the catalyst and reaction materials are difficult to separate, the product purity is reduced, meanwhile, the kettle-type reactor is corroded, and the reaction time and the reaction cost are improved.
Chemical reactions taking place in the sulfuric acid process reactor:
3CH 2 o (Formaldehyde) → C 3 H 6 O 3 (trioxymethylene)
C 3 H 6 O 3 (trioxymethylene) → 3CH 2 O (Formaldehyde)
2CH 2 O (Formaldehyde) + H 2 O (water) → CH 3 OH (methanol) + HCOOH (formic acid)
CH 3 OH (methanol) + HCOOH (formic acid) → HCOOCH 3 (methyl formate) + H 2 O (Water)
Based on exist among the above-mentioned prior art not enough, the embodiment of the utility model provides a trioxymethylene's production system, this trioxymethylene's production system is used for improving the one-way conversion rate of formaldehyde to improve the purity of the trioxymethylene who makes, reduce energy consumption and reaction cost.
Fig. 1 illustrates a schematic structural diagram of a trioxymethylene production system provided by an embodiment of the present invention. As shown in figure 1, the trioxymethylene production system comprises a trioxymethylene reaction device and a separation and purification device communicated with the trioxymethylene reaction device. The trioxymethylene reaction equipment is used for carrying out trimerization cyclization reaction on a formaldehyde solution in the reaction equipment to obtain a ternary azeotrope containing trioxymethylene, and then sending the ternary azeotrope into separation and purification equipment for separation and purification operation to obtain the trioxymethylene.
As shown in fig. 1, the trioxymethylene reaction apparatus may include a catalytic distillation column 1, wherein the catalytic distillation column 1 has an inlet and an outlet, and the outlet of the catalytic distillation column 1 is connected to a separation and purification apparatus. Along the direction of the top of catalytic rectification tower 1 to the bottom of catalytic rectification tower 1, this catalytic rectification tower 1 divide into rectifying section 11 in proper order, catalytic reaction section 12 and stripping section 13, and rectifying section 11 and stripping section 13 constitute by 1 ~ 3 layers of regular packing. In this case, the catalytic distillation column 1 has a first outlet at the top thereof and a second outlet at the bottom thereof.
In practical application, the catalytic rectifying tower 1 can be used as a reaction device, formaldehyde solution is fed into the catalytic reaction section 12 of the catalytic rectifying tower 1 from the inlet of the catalytic rectifying tower 1, trimerization cyclization reaction is carried out on the formaldehyde solution to obtain a liquid-phase product containing trioxymethylene, and the trioxymethylene is separated from the liquid-phase product in the catalytic reaction section 12 and enters an ascending gas phase. The ascending gas phase is further concentrated in the rectifying section 11 to obtain ternary azeotrope of trioxymethylene, water and formaldehyde, the ternary azeotrope is extracted from the first outlet of the catalytic rectifying tower 1 and sent into separation and purification equipment for separation and purification, and the trioxymethylene is obtained. The embodiment of the utility model provides an in catalytic distillation tower 1, catalytic reaction through with formaldehyde sets up and goes on in catalytic distillation tower 1's inside, and accomplish the back at catalytic reaction, continue to separate the liquid phase product that contains trioxymethylene at catalytic distillation tower 1's catalytic reaction section 12, separate into the top of the gaseous phase flow direction catalytic distillation tower 1 with the reaction product, thereby the concentration of the reaction product in the liquid phase product that contains trioxymethylene has been reduced, reversible reaction's balance restriction has been broken, make the one-way conversion rate of formaldehyde obtain promoting, thereby make the energy consumption of the trioxymethylene that the preparation obtained reduce.
As shown in figure 1, in order to improve the catalytic efficiency of the catalyst and reduce the influence of impurities on the activity of the catalyst, the embodiment of the present invention provides a trioxymethylene reaction apparatus, which further comprises a pretreatment assembly, wherein the outlet of the pretreatment assembly is communicated with the inlet of the catalytic rectification column 1. The pretreatment component is used for preheating and impurity removal treatment of formaldehyde solution introduced into the catalytic distillation tower 1.
As shown in FIG. 1, the separation and purification equipment may comprise an extraction column 2 and a product column 3, and purification of trioxymethylene is performed by the extraction column 2 and the product column 3. The top and the bottom of the extraction tower 2 are respectively provided with an inlet, the top and the bottom of the extraction tower 2 are respectively provided with an outlet, and the inlet at the top of the extraction tower 2 is communicated with the outlet of the catalytic rectification tower 1. The extraction tower 2 is internally provided with 2-5 scattered packing layers, and the scattered packing layers can be Raschig rings, pall rings, ladder rings, rectangular saddle rings and the like, which are not limited herein. Of course, the extraction column 2 may also have 2 to 5 layers of structured packing layers inside, and the structured packing layers and the bulk packing are all commercially available products, and are not limited herein.
In practical application, dichloroethane is selected as an extracting agent in the extraction tower 2, the dichloroethane is fed into the extraction tower 2 from an inlet at the bottom of the extraction tower 2, and the ternary azeotrope fed into the extraction tower 2 is subjected to extraction separation treatment to obtain an extraction phase containing trioxymethylene. The extraction distribution coefficient of dichloroethane is more than one time greater than that of benzene in the prior art, so that the solubility of trioxymethylene in dichloroethane is far greater than that in benzene, the extraction efficiency using dichloroethane as an extracting agent is remarkably improved compared with the prior art, the energy consumption in the separation and purification process is remarkably reduced, and the production cost is saved.
As shown in fig. 1, the product tower 3 has an inlet in the middle, and the top and bottom of the product tower 3 have outlets respectively, wherein the inlet in the middle of the product tower 3 is communicated with the outlet in the top of the extraction tower 2, and 60 to 120 sieve trays are arranged in the product tower 3.
In practical application, the extract phase can be extracted from the outlet of the top of the extraction tower 2 and then sent into the product tower 3 from the inlet of the product tower 3, separation and purification treatment is carried out in the product tower 3, trioxymethylene is obtained at the outlet of the bottom of the product tower 3, and a mixed solution containing the extracting agent and formaldehyde is obtained at the outlet of the top of the product tower 3.
As shown in FIG. 1, the separation and purification apparatus may further include a phase separation device 4 and a recovery tower 5 for treating the extractant and the waste liquid after the reaction. Wherein, phase separation device 4 sets up the top of the tower in product tower 3, and phase separation device 4 has entry, first export and second export, and the export that is located the top of the tower of product tower 3 communicates with the entry of phase separation device 4, and the first export of phase separation device 4 communicates with the entry of extraction column 2, and the second export of phase separation device 4 communicates with the entry of recovery column 5.
In practical application, a mixed solution containing the extracting agent and the formaldehyde is obtained from an outlet at the top of the product tower 3, the mixed solution is sent into the phase separation device 4 from an inlet of the phase separation device 4, and the dichloroethane and the dilute formaldehyde solution are separated from the mixed solution in the phase separation device 4 by natural sedimentation and stratification. Then, dilute formaldehyde solution is extracted from a second outlet of the phase separation device 4 and sent to a recovery tower 5 for concentration to obtain concentrated formaldehyde solution, and the concentrated formaldehyde solution is sent to the catalytic rectification tower 1 for recycling. The extractant is extracted from the first outlet of the phase separation device 4 and sent to the extraction tower 2 for recycling, so that raw materials are saved, and the cost is saved.
As shown in fig. 1, the recovery column 5 has an inlet, an outlet at the top of the recovery column 5, and an outlet at the bottom of the recovery column 5. Wherein, the inlet of the recovery tower 5 is respectively communicated with the outlet at the bottom of the catalytic rectifying tower 1 and the outlet at the bottom of the extraction tower 2, and is used for recovering the dilute formaldehyde solution generated in the catalytic rectifying tower 1 or the extraction tower 2. In practical application, in the operation process of the trioxymethylene production system, the tower bottoms of the catalytic rectifying tower 1 and the extracting tower 2 may generate dilute formaldehyde solutions, so that the dilute formaldehyde solution can be extracted at the outlet of the tower bottom of the catalytic rectifying tower 1, the dilute formaldehyde solution can be extracted at the outlet of the tower bottom of the extracting tower 2, and the dilute formaldehyde solution can be extracted from the outlet of the tower bottom of the catalytic rectifying tower 1 and the outlet of the tower bottom of the extracting tower 2, and then the dilute formaldehyde solution is sent into the recovering tower 5 from the inlet of the recovering tower 5 for concentration to obtain the concentrated formaldehyde solution. The concentration of the dilute formaldehyde solution may be 40% to 50%.
As shown in fig. 1, the outlet at the top of the recovery tower 5 may be communicated with the inlet of the catalytic distillation tower 1, or may be communicated with the inlet of the pretreatment module, and is used for feeding the concentrated formaldehyde solution into the catalytic distillation tower 1 or into the pretreatment module. An outlet at the bottom of the recovery column 5 is used for discharging the waste water after the reaction. It should be noted here that whether the concentrated formaldehyde solution is fed into the catalytic distillation column 1 or the pretreatment module may be selected according to the actual situation. For example, in the case where it is determined that the temperature of the concentrated formaldehyde solution does not meet the preset temperature requirement, the concentrated formaldehyde solution needs to be sent to a pretreatment module communicated with the outlet of the top of the recovery column 5 for preheating treatment, so as to improve the catalytic efficiency of the solid acid catalyst bed 61 of the catalytic distillation column 1.
For another example, in the case where it is determined that impurities are present in the concentrated formaldehyde solution, the concentrated formaldehyde solution needs to be fed to a pretreatment module communicating with the top outlet of the recovery column 5 to perform solid filtration. It should be noted that the impurities may be silt in the pipeline, iron filings generated after the production system is corroded, and the like.
For another example, in the case where it is determined that the metal ions are present in the concentrated formaldehyde solution, the concentrated formaldehyde solution is fed to a pretreatment module communicating with the top outlet of the recovery column 5 to be subjected to metal ion filtration. The metal ions herein may be iron ions, sodium ions, or the like.
Fig. 2 illustrates a schematic partial structural diagram of a catalytic reaction section of a catalytic distillation tower provided by an embodiment of the present invention. As shown in fig. 2, the trioxymethylene reaction apparatus includes a catalytic distillation column 1, and the catalytic reaction section 12 of the catalytic distillation column 1 specifically includes a plurality of reaction units 6 distributed along the height direction of the catalytic distillation column 1, and each reaction unit 6 includes a solid acid catalyst bed 61 and a gas-liquid phase mass transfer structure 62 distributed along the height direction of the catalytic distillation column 1. The number of the reaction units 6 can be calculated according to the feeding amount of the formaldehyde solution and the conversion rate, the number of the reaction units 6 can be 6 to 14, preferably, the number of the reaction units 6 can be 6 to 12, and more preferably, the number of the reaction units 6 can be 6 to 10. In practical use, the formaldehyde solution can be fed into the catalytic rectification tower 1 to obtain the ternary azeotrope. Wherein, the concentration of the formaldehyde solution is 65-75%. The solid acid catalyst bed layer 61 is used for catalyzing a formaldehyde solution to perform trimerization cyclization reaction to obtain a liquid-phase reaction product containing trioxymethylene, and the gas-liquid-phase mass transfer structure 62 is used for separating part of trioxymethylene from the liquid-phase reaction product. Because the catalytic reaction section 12 of the catalytic rectification tower 1 is provided with the plurality of reaction units 6 distributed along the height direction of the catalytic rectification tower 1, when the formaldehyde solution flows through one reaction unit 6, a liquid-phase reaction product containing trioxymethylene is obtained after the catalysis of the solid acid catalyst bed layer 61, and the liquid-phase reaction product containing trioxymethylene comprises the formaldehyde solution and trioxymethylene. The liquid phase reaction product is then separated in a gas-liquid phase mass transfer structure 62, allowing trioxymethylene to pass from the liquid phase product into the gas phase. The formaldehyde solution which is not separated and has not reacted completely is continuously catalyzed by the solid acid catalyst bed layer 61 in the next reaction unit 6, is separated in the gas-liquid phase mass transfer structure 62, and is treated by a plurality of reaction units 6, the trioxymethylene which is a reaction product is continuously separated, so that the concentration of the trioxymethylene which is a reaction product in the liquid phase reaction product is reduced, the trimerization cyclization reaction of the formaldehyde is continuously and positively carried out, the conversion rate of the formaldehyde per pass is improved, and the energy consumption for producing the trioxymethylene is reduced.
As shown in FIG. 2, in the same reaction unit 6, the distribution directions of the solid acid catalyst bed 61 and the gas-liquid phase mass transfer structure 62 can be selected according to actual conditions. For example, the solid acid catalyst bed 61 and the gas-liquid phase mass transfer structure 62 may be distributed along the direction of increasing height of the catalytic rectification column 1. For another example, the solid acid catalyst bed 61 and the gas-liquid phase mass transfer structure 62 may be distributed along the height decreasing direction of the catalytic rectification column 1.
As shown in fig. 2, the solid acid catalyst bed 61 may contain a solid acid catalyst. The solid acid catalyst can be one or more of resin, molecular sieve, supported ionic liquid and alumina. For example, the solid acid catalyst bed 61 may be a resin-containing solid acid catalyst bed 61, a molecular sieve-containing solid acid catalyst bed 61, or a resin-and molecular sieve-containing solid acid catalyst bed 61. The catalyst may be a solid acid catalyst bed 61 containing a supported ionic liquid, or may be a solid acid catalyst bed 61 containing alumina, or the like. More specifically, the solid acid catalyzesThe agent bed layer 61 may be a solid acid catalyst bed layer 61 containing a strong acid cation exchange resin, may be a solid acid catalyst bed layer 61 containing an acid catalyst type molecular sieve, may be a solid acid catalyst bed layer 61 containing a strong acid cation exchange resin and an acid catalyst type molecular sieve, and the like. In this case, the combination of the strong acid cation exchange resin and the acid catalyst type molecular sieve may be a combination of a stack of the strong acid cation exchange resin and the acid catalyst type molecular sieve, or a combination of a mixture of the strong acid cation exchange resin and the acid catalyst type molecular sieve, but is not limited thereto. It should be understood that the strongly acidic cation exchange resin herein refers to a type of ion exchange resin containing a large number of strongly acidic groups, which readily dissociate H in solution + And therefore, is strongly acidic, such as polystyrene sulfonic acid type resin, etc. The molecular sieve containing an acid catalyst refers to a molecular sieve which performs a catalytic reaction by utilizing the surface acidity of the molecular sieve. The acid catalyst type molecular sieve can be one or a combination of more of a ZSM5 type molecular sieve, a Beta type molecular sieve and a Y type molecular sieve, for example, the acid catalyst type molecular sieve can be a ZSM5 type molecular sieve, a Beta type molecular sieve, a Y type molecular sieve, a ZSM5 type molecular sieve, a Y type molecular sieve and the like. The supported ionic liquid can be 1- (3-sulfopropyl) cyclohexylimine dodecaphosphotungstate, 1- (3-sulfopropyl) cyclohexylimine dodecaphosphomolybdate and the like.
As shown in fig. 2, because the embodiment of the present invention provides a catalytic distillation tower 1 in which the catalyst is solid acid catalyst, therefore, the structure of the solid acid catalyst bed 61 can be set to a fixed bed structure, so that the reaction material and the solid acid catalyst can be separated more easily, the occurrence of side reactions is reduced, the impurity content in the subsequent processes is reduced, the energy consumption for separation is reduced, the corrosion of the catalyst to the trioxymethylene production system is reduced, and the production cost is saved. Therefore, in the trioxymethylene production system that the embodiment of the utility model provides, catalytic distillation tower 1 can use 316L stainless steel as raw and other equipment can use 304L stainless steel as raw and other materials can.
As shown in fig. 2, the filling height of the solid acid catalyst bed layer 61 needs to be calculated according to the feeding amount of the formaldehyde solution and the conversion rate, and in practical application, the filling height of the solid acid catalyst bed layer 61 may be 1m to 3m to ensure the catalytic effect of the solid acid catalyst bed layer 61. The distance between the solid acid catalyst bed layer 61 and the gas-liquid phase mass transfer structure 62 can be 100 mm-300 mm, so that the liquid phase product can be ensured to flow into the gas-liquid phase mass transfer structure 62 for sufficient separation after being subjected to sufficient reaction on the solid acid catalyst bed layer 61.
As shown in fig. 2, the gas-liquid phase mass transfer structure 62 may be a separation tray structure or a packing structure for separating liquid phase products. The packing structure can be structured packing or random packing, and the structured packing and the random packing are all commercial products and are not described in detail herein.
As shown in fig. 2, the above-mentioned separation tray structure includes at least two separation trays, and in practical application, the number of the separation steps disposed between two solid acid catalyst beds 61 may be 2 to 6. The separation trays of each layer may be provided as single-overflow separation trays or double-overflow separation trays.
As shown in fig. 2, each reaction unit 6 may further include a liquid distributor (not shown) located on a side of the solid acid catalyst bed 61 away from the gas-liquid phase mass transfer structure 62, for introducing the formaldehyde solution into the solid acid catalyst bed 61 to ensure that the formaldehyde solution can sufficiently contact with the solid acid catalyst bed 61 to perform trimerization cyclization reaction.
As shown in fig. 2, the reaction apparatus may further include a pretreatment module communicated with an inlet of the catalytic distillation tower 1, and the pretreatment module is configured to at least one of preheat and filter the formaldehyde solution introduced into the catalytic distillation tower 1. The preheating temperature is 90-110 ℃.
As shown in fig. 2, the pretreatment module includes at least one of a preheater 7, a physical filter 8, and an ion exchange filter 9. The preheater 7 is used for heating the formaldehyde solution, so that the catalytic efficiency is improved, the energy consumption is saved, the physical filter 8 is used for removing solid impurities in the formaldehyde solution, and the ion exchange filter 9 is used for removing metal ions in the formaldehyde solution, so that the service life of the solid acid catalyst is prolonged. The adsorbent contained in the ion exchange filter 9 may be a molecular sieve, an ion exchange resin, or a mixture of a molecular sieve and an ion exchange resin. It should be noted that the molecular sieve and the ion exchange resin are commercially available products, and are not described herein again. When the formaldehyde solution introduced into the catalytic distillation tower 1 needs to be preheated, the pretreatment component comprises a preheater 7. When the formaldehyde solution introduced into the catalytic distillation column 1 needs to be filtered, the pretreatment module may include at least one of a physical filter 8 and an ion exchange filter 9.
In practical application, before the formaldehyde solution is fed into the catalytic distillation tower 1, the formaldehyde solution can be subjected to at least one treatment selected from preheating, solid filtering and metal ion filtering according to practical conditions. Wherein, the filtering mode of the solid filtering is a physical filtering mode, and the used equipment is a physical filter 8. The filtering mode of the metal ion filtering is an adsorption type filtering mode, the adsorbent of the adsorption type filtering mode is a molecular sieve or ion exchange resin, and the used equipment is an ion exchange type filter 9.
As shown in fig. 2, since the purification column is saturated and needs to be regenerated, the ion exchange filter 9 includes a plurality of purification columns communicating with the inlet of the catalytic distillation column 1. When one of the purifying towers is in the working state, the other purifying towers are in the non-working state. When the purifying tower normally operates, the formaldehyde solution is sent into the purifying tower from the tower top of the purifying tower for purification treatment, and when in regeneration, the regeneration liquid enters the purifying tower from the tower bottom of the purifying tower for regeneration treatment of the purifying tower.
The present invention provides a trioxymethylene reaction apparatus and a production system thereof will be described in detail with reference to the following examples, which are merely illustrative and not limitative of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
Example 1
In this embodiment, taking a production system for producing 50000 tons of trioxymethylene annually as an example, 8000 hours of annual operation are counted, a formaldehyde solution with a concentration of 75% is used as a raw material, a solid acid catalyst bed layer is a solid acid catalyst bed layer containing a strong acid cation exchange resin, and the mass percentage of main components of each stream in the production system for trioxymethylene is shown in table 1:
TABLE 1 Mass content Table
The amount of formaldehyde solution consumed by a 50000 ton/year trioxymethylene production system is about 8.5t/h, the raw material is heated to 90 ℃ by using low-pressure steam in a preheater, and the amount of formaldehyde solution circulated from the top of a recovery tower is about 9.5t/h, so that the amount of raw material fed to a catalytic distillation tower is about 18 t/h. The operation pressure of the catalytic rectifying tower is adjusted to be 150kPaG, the tower top temperature of the catalytic rectifying tower is 90 ℃, and the reflux ratio of the catalytic rectifying tower is 2.5. The rectifying section of the catalytic rectifying tower is provided with 1 layer of regular packing, the packing height is 6m, the stripping section is provided with 1 layer of regular packing, the packing height is 6m, the catalytic reaction section is provided with 6 reaction units, namely, the number of the solid acid catalyst beds is 6 layers, the filling height of the solid acid catalyst beds is 1m, 2 single-overflow separation tower plates are arranged between two adjacent solid acid catalyst beds, and the distance between the solid acid catalyst beds and the adjacent single-overflow separation tower plates is 200 mm. In the catalytic distillation tower of the trioxymethylene production system, the conversion per pass of formaldehyde is about 52%.
The operating pressure of the extraction tower is 100kPaG, the temperature at the top of the extraction tower is 65 ℃, the ratio of the feeding amount of the process materials to the feeding amount of the extracting agent in the extraction tower is 1.5:1, 3 scattered packing layers are arranged in the extraction tower, and the height of each layer is 5 m. The operating pressure of the product tower is 150kPaG, the temperature at the top of the tower is 100 ℃, the reflux ratio is 2.5, 40 sieve plate trays are arranged in the rectifying section of the product tower, and 50 sieve plate trays are arranged in the stripping section. The operating pressure of the recovery tower is 700kPaG, the temperature at the top of the tower is 160 ℃, the reflux ratio is 0.5, 50 sieve tray plates are arranged at the rectifying section of the recovery tower, and 50 sieve tray plates are arranged at the stripping section.
The flow rate of trioxymethylene at the bottom of the product tower is about 6.4t/h, the quantity of wastewater at the bottom of the recovery tower is about 2.1t/h, medium-pressure steam is used as a reboiler heat source at the bottom of the recovery tower, low-pressure steam reboiler heat sources are used at the bottoms of the catalytic rectifying tower and the product tower, and circulating water is used as a cold source in all condensers in the trioxymethylene production system.
Example 2
In this embodiment, taking a production system for producing 50000 tons of trioxymethylene every year as an example, 8000 hours of annual operation are counted, a formaldehyde solution with a concentration of 65% is used as a raw material, a solid acid catalyst bed layer is a solid acid catalyst bed layer containing a ZSM5 type molecular sieve, and mass percentage contents of main components of each stream in the production system for producing trioxymethylene are shown in table 2:
TABLE 2 Mass content table
The amount of the formaldehyde solution consumed by a 50000 ton/year production system for trioxymethylene is about 9.6t/h, the raw material is heated to 110 ℃ in the preheater by using low-pressure steam, and the amount of the formaldehyde solution circulated from the top of the recovery tower is about 11.1t/h, so that the amount of the raw material fed to the catalytic distillation tower is about 20.7 t/h. The operation pressure of the catalytic rectifying tower is adjusted to be 250kPaG, the tower top temperature of the catalytic rectifying tower is 100 ℃, and the reflux ratio of the catalytic rectifying tower is 3.5. 3 layers of regular packing are arranged in a rectifying section of the catalytic rectifying tower, the height of the packing is 6m, 2 layers of regular packing are arranged in a stripping section, the height of the packing is 6m, 14 reaction units are arranged in a catalytic reaction section, namely, the number of solid acid catalyst beds is 14, the filling height of each solid acid catalyst bed is 3m, 6 packing layers are arranged between every two adjacent solid acid catalyst beds, and the distance between each solid acid catalyst bed and the adjacent packing layer is 300 mm. In the catalytic distillation tower of the trioxymethylene production system, the conversion per pass of formaldehyde is about 48%.
The operating pressure of the extraction tower is 150kPaG, the temperature at the top of the extraction tower is 70 ℃, the ratio of the feeding amount of the process materials to the feeding amount of the extracting agent in the extraction tower is 1.5:1, 2 layers of random packing layers are arranged in the extraction tower, and the height of each layer is 5 m. The operating pressure of the product tower is 200kPaG, the temperature at the top of the tower is 105 ℃, the reflux ratio is 2.7, 30 sieve plate tower plates are arranged in the rectifying section of the product tower, and 30 sieve plate tower plates are arranged in the stripping section. The operation pressure of the recovery tower is 800kPaG, the temperature at the top of the tower is 170 ℃, the reflux ratio is 1.0, 40 sieve plate trays are arranged at the rectifying section of the recovery tower, and 50 sieve plate trays are arranged at the stripping section.
The flow rate of trioxymethylene at the bottom of the product tower is about 6.4t/h, the quantity of wastewater at the bottom of the recovery tower is about 3.4t/h, medium-pressure steam is used as a reboiler heat source at the bottom of the recovery tower, low-pressure steam reboiler heat sources are used at the bottoms of the catalytic rectifying tower and the product tower, and circulating water is used as a cold source in all condensers in the trioxymethylene production system.
Example 3
In this embodiment, taking a production system for producing 50000 tons of trioxymethylene annually as an example, 8000 hours of annual operation are counted, a formaldehyde solution with a concentration of 70% is used as a raw material, a solid acid catalyst bed layer is a solid acid catalyst bed layer containing a Beta-type molecular sieve, and the mass percentage of the main components of each stream in the production system for trioxymethylene is shown in table 3:
TABLE 3 Mass content table
The amount of formaldehyde solution consumed by a 50000 ton/year trioxymethylene production system is about 8.9t/h, the raw material is heated to 100 ℃ by using low-pressure steam in a preheater, and the amount of formaldehyde solution circulated from the top of a recovery tower is about 10.4t/h, so that the amount of raw material fed to a catalytic distillation tower is about 19.3 t/h. The operation pressure of the catalytic rectifying tower is adjusted to be 200kPaG, the tower top temperature of the catalytic rectifying tower is 95 ℃, and the reflux ratio of the catalytic rectifying tower is 3.0. The rectifying section of the catalytic rectifying tower is provided with 2 layers of structured packing, the height of the packing is 6m, the stripping section is provided with 3 layers of structured packing, the height of the packing is 6m, the catalytic reaction section is provided with 10 reaction units, namely, the number of the solid acid catalyst bed layers is 10, the filling height of the solid acid catalyst bed layers is 2.5m, 4 double-overflow separation tower plates are arranged between two adjacent solid acid catalyst bed layers, and the distance between the solid acid catalyst bed layers and the adjacent double-overflow separation tower plates is 100 mm. In the catalytic distillation tower of the trioxymethylene production system, the conversion per pass of formaldehyde is about 50%.
The operating pressure of the extraction tower is 200kPaG, the temperature at the top of the extraction tower is 75 ℃, the ratio of the feeding amount of the process materials to the feeding amount of the extracting agent in the extraction tower is 1.5:1, 5 layers of structured packing layers are arranged in the extraction tower, and the height of each layer is 5 m. The operation pressure of the product tower is 250kPaG, the temperature at the top of the tower is 110 ℃, the reflux ratio is 3.5, 50 sieve plate tower plates are arranged at the rectifying section of the product tower, and 70 sieve plate tower plates are arranged at the stripping section. The operating pressure of the recovery tower is 900kPaG, the temperature at the top of the tower is 180 ℃, the reflux ratio is 1.5, 60 sieve plate trays are arranged at the rectifying section of the recovery tower, and 60 sieve plate trays are arranged at the stripping section.
The flow rate of trioxymethylene at the bottom of the product tower is about 6.4t/h, the quantity of wastewater at the bottom of the recovery tower is about 2.7t/h, medium-pressure steam is used as a reboiler heat source at the bottom of the recovery tower, low-pressure steam reboiler heat sources are used at the bottoms of the catalytic rectifying tower and the product tower, and circulating water is used as a cold source in all condensers in the trioxymethylene production system.
According to the experimental results of the embodiments 1 to 3, it can be seen that when trioxymethylene is prepared by the reaction method of trioxymethylene and the production method thereof provided by the embodiments of the present invention, the conversion per pass of formaldehyde is increased from 26% in the prior art to more than 48%. And as can be seen from tables 1 to 3, the purity of the trioxymethylene prepared is above 99%. Therefore, the embodiment of the utility model provides a trioxymethylene's reaction method and production method can improve the conversion per pass of formaldehyde to improve the purity of the trioxymethylene that the reaction prepared, reduced energy consumption and reaction cost.
In the foregoing description of embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.
The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (13)
1. A trioxymethylene reaction device is characterized by comprising a catalytic rectification tower, wherein the catalytic rectification tower comprises a plurality of reaction units distributed along the height direction of the catalytic rectification tower, and each reaction unit comprises a solid acid catalyst bed layer and a gas-liquid phase mass transfer structure distributed along the height direction of the catalytic rectification tower;
in the same reaction unit, the solid acid catalyst bed layer and the gas-liquid phase mass transfer structure are distributed along the height increasing direction of the catalytic rectification tower; or the solid acid catalyst bed layer and the gas-liquid phase mass transfer structure are distributed along the height reduction direction of the catalytic rectification tower.
2. A trioxymethylene reaction apparatus as set forth in claim 1, wherein the number of said reaction units is 6 to 14.
3. A trioxymethylene reaction apparatus according to claim 1, wherein the structure of the solid acid catalyst bed is a fixed bed structure; and/or the presence of a gas in the atmosphere,
the filling height of the solid acid catalyst bed layer is 1 m-3 m; and/or the presence of a gas in the atmosphere,
the distance between the solid acid catalyst bed layer and the gas-liquid phase mass transfer structure is 100-300 mm.
4. A trioxymethylene reaction apparatus as set forth in claim 1, wherein said gas-liquid phase mass transfer structure is a separation tray structure or a packing structure.
5. A trioxymethylene reaction apparatus as set forth in claim 4, wherein said separation tray structure comprises at least two separation trays, each of which is a single overflow separation tray or a double overflow separation tray.
6. A trioxymethylene reaction apparatus as set forth in claim 1, wherein each of said reaction units further comprises a liquid distributor located at a side of said solid acid catalyst bed facing away from said gas-liquid phase mass transfer structure.
7. A trioxymethylene reaction equipment as claimed in any one of claims 1 to 6, wherein the reaction equipment further comprises a pretreatment assembly communicated with the inlet of the catalytic rectification tower, and the pretreatment assembly is used for preheating and/or filtering the formaldehyde solution introduced into the catalytic rectification tower.
8. A trioxymethylene reaction apparatus as set forth in claim 7, wherein said pretreatment module comprises at least one of a preheater, a physical filter, and an ion exchange filter.
9. A trioxymethylene reaction apparatus according to claim 8, wherein the ion exchange filter comprises a plurality of purification columns communicating with an inlet of the catalytic rectification column; one of the purification towers is in a working state, and the rest of the purification towers are in a non-working state; and/or the presence of a gas in the gas,
the adsorbent contained in the ion exchange filter comprises a molecular sieve and/or an ion exchange resin.
10. A trioxymethylene production system characterized by comprising the trioxymethylene reaction apparatus as set forth in any one of claims 1 to 9, and a separation and purification apparatus communicating with an outlet of a catalytic distillation column included in the trioxymethylene reaction apparatus.
11. A trioxymethylene production system according to claim 10, wherein the separation and purification apparatus comprises an extraction column, and a product column communicating with an outlet of the extraction column, and an outlet of the catalytic distillation column communicates with an inlet of the extraction column.
12. A trioxymethylene production system as set forth in claim 11, wherein said separation and purification apparatus further comprises a phase separation device and a recovery column, an outlet of said product column is communicated with an inlet of said phase separation device, a first outlet of said phase separation device is communicated with an inlet of said extraction column, and a second outlet of said phase separation device is communicated with an inlet of said recovery column.
13. A trioxymethylene production system as set forth in claim 12, wherein the reaction apparatus contains a pretreatment module, and the outlet of the recovery column is communicated with the inlet of the catalytic rectification column and/or the inlet of the pretreatment module.
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